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Software-defined radio (SDR) is an important technology that underlies many modern wireless communications

systems. For example, mostcell-phone handsetsand wireless routersare based on SDR technology.Thistechnology is popular among computer scientists, with several interesting software projects underway, such as theGNU radio

and FlexRadio’s SDR 1000

and SDR 5000.

Essentially,

SDR replaces

much of the electronics in a radio with software. By substituting many hardwarecomponents for software, SDR providesflexibility with baseband waveforms, frequencies, and features. Thesoftware necessary to drive an SDR includes real-time signal processing,auser interface, and other processingtasks.Therefore, an SDR is a self-contained,

embedded software system with real-time deadlines and hardwareinterfaces.

Software-defined radiosrely on some hardware, minimally a down-converter and A/D for receiving and a D/A andanup-converter for transmitting. While the hardware circuitry is well

defined, itcan be challenging to

buildbecauseradiooperating frequencies are, naturally enough, in the radio frequency (RF) spectrum. While cell phonesare typically in the GHz range, our applications are in the0.1MHz

–

100 MHz range, specially, theamateur, publicservice,

and commercial radio bands.

Areas ofOngoing

Research

The SDR has become a popular research project

with the following applications.

SDR and

PublicSafety

In this project, we are

developing

inexpensive, Pocket

PC-based SDR systemsfor public-safety applications.

Creating these “portable” SDRs

will

allow emergency personnel touse

a variety of radio bands during disasters. Inaddition, these radios will work on the amateur radio frequencies.

Because most communications systems otherthan amateur radio go down during

disasters, SDR could allow emergency personnel to gain the information theyneed in a dependable fashion.Additionally, there were significant communications mismatches between police,firefighters and other emergency personnel during Hurricane Katrina and the September 11th

terrorist attacks. Theflexibility of SDR could help to rectify miscommunication

between different branches of public servants.

SDR and

“High-Definition” Radio

We are developing additional

plug-ins for

commercial radio broadcasts of digital AM and FM, commonly called“high-definition” radio. These new waveforms are intended to give AM radio the quality of current FM stations andto

broadcast

FM stationsatthe quality of CDs.

Based on the

SDRlibrary software, wearebuildingdecoders for these waveforms. This is a pure softwareproject using the same down-converting hardware as the other SDR projects.

Mobile Gaming Platforms

Mobile gaming is an important emerging technology. Electronic Arts,Microsoft, and Google, for example,have made major commitments to mobility. We are interested in developing high-performance computing andcommunication platforms specifically to support mobile gaming, communication and computation.

Course Opportunities

Interested students are encouraged to take Computer Science department courses in digital-signalprocessing and inSDR. These courses provide the in-depth exposure to the mathematics, software, and systemconcepts in SDR.

Research Opportunities

Interested students, from sophomore through senior years, are encouraged to participate inthese